tutorial that I can not improve on :) The only thing I do suggest is if you decide to hang yours from the front porch or a tree, be sure to really tape the trash bags in the area where you will make holes for wire or yarn to hold him. I lay a few layers of tape (unless it's good duct tape and I will make only one layer) overtop of each other and pierce through the layers and the bag to slip my warn or wire through.
Have fun and enjoy trying to figure out a face for yours! I realized ours looks a little bummed this year. Oh well, with the economy and all, I am sure he is feeling all our pain! ;)